For all these years, they’ve hidden the truth about the Kennedy assassination.

It didn’t require a conspiracy. It just took repeating a falsehood until it became conventional wisdom. The myth about the Kennedy assassination is that President John F. Kennedy, at great personal risk, traveled to Dallas, aka the City of Hate, and was somehow murdered by an atmosphere of intolerance. The truth is that he was shot by a Communist.

As James Piereson writes in his brilliant book Camelot and the Cultural Revolution, liberals had the choice after the assassination to make Kennedy a martyr to civil rights or admit that he was a casualty of the Cold War. They found the notion of Kennedy dying for racial progress much more congenial and useful, even though it depended on a rank distortion.

The interpretive misdirection began in the immediate aftermath of Lee Harvey Oswald’s act of murder. Pundits and analysts still follow the well-worn script, often boiling down their indictment to one word: Dallas. The epigraph of the new book Dallas 1963 is a letter to the mayor at the time: “Dallas, the city that virtually invited the poor insignificant soul who blotted out the life of President Kennedy to do it in Dallas.”

Slate calls a letter to Kennedy’s press secretary warning JFK not to visit Dallas because he might be killed by a right-wing mob “eerily prophetic,” which would be unassailably true . . . if Kennedy had been killed by a right-wing mob.

In a New York Times op-ed, history scholar James McAuley calls Dallas “the city that willed the death of the president.” Who knew that municipalities had such frightening powers? George W. Bush is lucky he wasn’t killed in office by Burlington, Vt., or Berkeley, Calif.

In a news report, Timesman Manny Fernandez writes of the “painful, embarrassing memories of the angry anti-Washington culture that flourished here 50 years ago — and now seems a permanent part of the national mood.”

Get it? The rancid political culture of Dallas that was responsible for the death of Kennedy lives on today in the Tea Party, which needs to be stopped before it kills again.

There are at least two problems with all this. The first is that cities don’t kill people. Neither does political hostility. There was plenty of kookery, racism, and ugliness in Dallas circa 1963 — and much derision and abuse of Kennedy — but none of those things picked up a rifle and shot the president of the United States.

The second — and amazingly enough, saying it still carries a subversive hint of revisionism — is that Oswald was a thoroughgoing Communist.

As Piereson recounts, Oswald tried to defect to the Soviet Union. He told a reporter that his reasons were “purely political.” Trying to renounce his citizenship, he gave a note to an official at the U.S. Embassy in the Soviet Union that said, “I affirm my allegiance to the Union of Soviet Socialist Republics” and “I am a Marxist.”

Eventually, he returned to the United States and grew disillusioned with the Soviet Union but not with the idea of revolution as exemplified by Fidel Castro’s Cuba. He subscribed to The Militant, published by the Socialist Workers Party, and the Daily Worker, published by the Communist Party. He posed for a photograph holding both publications and the rifle he would use to shoot Kennedy.

Oswald had hoped to travel to Cuba and serve in Castro’s government. To establish his bona fides, he set up a chapter of the “Fair Play for Cuba” committee during a stay in New Orleans. He traveled to Mexico City and visited the Cuban and Soviet embassies in his bid to get to Cuba. He was still trying to navigate the bureaucracy when he heard Kennedy would be visiting Dallas.

The Kennedy assassination has always invited elaborate theories about a cover-up of the truth about that awful day. But it’s not complicated. The lie has always been in plain sight.